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-rw-r--r--gfx/harfbuzz/src/hb-buffer-verify.cc423
1 files changed, 423 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-buffer-verify.cc b/gfx/harfbuzz/src/hb-buffer-verify.cc
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+++ b/gfx/harfbuzz/src/hb-buffer-verify.cc
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+/*
+ * Copyright © 2022 Behdad Esfahbod
+ *
+ * This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#include "hb.hh"
+
+#ifndef HB_NO_BUFFER_VERIFY
+
+#include "hb-buffer.hh"
+
+
+#define BUFFER_VERIFY_ERROR "buffer verify error: "
+static inline void
+buffer_verify_error (hb_buffer_t *buffer,
+ hb_font_t *font,
+ const char *fmt,
+ ...) HB_PRINTF_FUNC(3, 4);
+
+static inline void
+buffer_verify_error (hb_buffer_t *buffer,
+ hb_font_t *font,
+ const char *fmt,
+ ...)
+{
+ va_list ap;
+ va_start (ap, fmt);
+ if (buffer->messaging ())
+ {
+ buffer->message_impl (font, fmt, ap);
+ }
+ else
+ {
+ fprintf (stderr, "harfbuzz ");
+ vfprintf (stderr, fmt, ap);
+ fprintf (stderr, "\n");
+ }
+ va_end (ap);
+}
+
+static bool
+buffer_verify_monotone (hb_buffer_t *buffer,
+ hb_font_t *font)
+{
+ /* Check that clusters are monotone. */
+ if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES ||
+ buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
+ {
+ bool is_forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
+
+ unsigned int num_glyphs;
+ hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
+
+ for (unsigned int i = 1; i < num_glyphs; i++)
+ if (info[i-1].cluster != info[i].cluster &&
+ (info[i-1].cluster < info[i].cluster) != is_forward)
+ {
+ buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "clusters are not monotone.");
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static bool
+buffer_verify_unsafe_to_break (hb_buffer_t *buffer,
+ hb_buffer_t *text_buffer,
+ hb_font_t *font,
+ const hb_feature_t *features,
+ unsigned int num_features,
+ const char * const *shapers)
+{
+ if (buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES &&
+ buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
+ {
+ /* Cannot perform this check without monotone clusters. */
+ return true;
+ }
+
+ /* Check that breaking up shaping at safe-to-break is indeed safe. */
+
+ hb_buffer_t *fragment = hb_buffer_create_similar (buffer);
+ hb_buffer_set_flags (fragment, (hb_buffer_flags_t (hb_buffer_get_flags (fragment) & ~HB_BUFFER_FLAG_VERIFY)));
+ hb_buffer_t *reconstruction = hb_buffer_create_similar (buffer);
+ hb_buffer_set_flags (reconstruction, (hb_buffer_flags_t (hb_buffer_get_flags (reconstruction) & ~HB_BUFFER_FLAG_VERIFY)));
+
+ unsigned int num_glyphs;
+ hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
+
+ unsigned int num_chars;
+ hb_glyph_info_t *text = hb_buffer_get_glyph_infos (text_buffer, &num_chars);
+
+ /* Chop text and shape fragments. */
+ bool forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
+ unsigned int start = 0;
+ unsigned int text_start = forward ? 0 : num_chars;
+ unsigned int text_end = text_start;
+ for (unsigned int end = 1; end < num_glyphs + 1; end++)
+ {
+ if (end < num_glyphs &&
+ (info[end].cluster == info[end-1].cluster ||
+ info[end-(forward?0:1)].mask & HB_GLYPH_FLAG_UNSAFE_TO_BREAK))
+ continue;
+
+ /* Shape segment corresponding to glyphs start..end. */
+ if (end == num_glyphs)
+ {
+ if (forward)
+ text_end = num_chars;
+ else
+ text_start = 0;
+ }
+ else
+ {
+ if (forward)
+ {
+ unsigned int cluster = info[end].cluster;
+ while (text_end < num_chars && text[text_end].cluster < cluster)
+ text_end++;
+ }
+ else
+ {
+ unsigned int cluster = info[end - 1].cluster;
+ while (text_start && text[text_start - 1].cluster >= cluster)
+ text_start--;
+ }
+ }
+ assert (text_start < text_end);
+
+ if (0)
+ printf("start %u end %u text start %u end %u\n", start, end, text_start, text_end);
+
+ hb_buffer_clear_contents (fragment);
+
+ hb_buffer_flags_t flags = hb_buffer_get_flags (fragment);
+ if (0 < text_start)
+ flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_BOT);
+ if (text_end < num_chars)
+ flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_EOT);
+ hb_buffer_set_flags (fragment, flags);
+
+ hb_buffer_append (fragment, text_buffer, text_start, text_end);
+ if (!hb_shape_full (font, fragment, features, num_features, shapers) ||
+ fragment->successful || fragment->shaping_failed)
+ {
+ hb_buffer_destroy (reconstruction);
+ hb_buffer_destroy (fragment);
+ return true;
+ }
+ hb_buffer_append (reconstruction, fragment, 0, -1);
+
+ start = end;
+ if (forward)
+ text_start = text_end;
+ else
+ text_end = text_start;
+ }
+
+ bool ret = true;
+ if (likely (reconstruction->successful))
+ {
+ hb_buffer_diff_flags_t diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0);
+ if (diff & ~HB_BUFFER_DIFF_FLAG_GLYPH_FLAGS_MISMATCH)
+ {
+ buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "unsafe-to-break test failed.");
+ ret = false;
+
+ /* Return the reconstructed result instead so it can be inspected. */
+ hb_buffer_set_length (buffer, 0);
+ hb_buffer_append (buffer, reconstruction, 0, -1);
+ }
+ }
+
+ hb_buffer_destroy (reconstruction);
+ hb_buffer_destroy (fragment);
+
+ return ret;
+}
+
+static bool
+buffer_verify_unsafe_to_concat (hb_buffer_t *buffer,
+ hb_buffer_t *text_buffer,
+ hb_font_t *font,
+ const hb_feature_t *features,
+ unsigned int num_features,
+ const char * const *shapers)
+{
+ if (buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES &&
+ buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
+ {
+ /* Cannot perform this check without monotone clusters. */
+ return true;
+ }
+
+ /* Check that shuffling up text before shaping at safe-to-concat points
+ * is indeed safe. */
+
+ /* This is what we do:
+ *
+ * 1. We shape text once. Then segment the text at all the safe-to-concat
+ * points;
+ *
+ * 2. Then we create two buffers, one containing all the even segments and
+ * one all the odd segments.
+ *
+ * 3. Because all these segments were safe-to-concat at both ends, we
+ * expect that concatenating them and shaping should NOT change the
+ * shaping results of each segment. As such, we expect that after
+ * shaping the two buffers, we still get cluster boundaries at the
+ * segment boundaries, and that those all are safe-to-concat points.
+ * Moreover, that there are NOT any safe-to-concat points within the
+ * segments.
+ *
+ * 4. Finally, we reconstruct the shaping results of the original text by
+ * simply interleaving the shaping results of the segments from the two
+ * buffers, and assert that the total shaping results is the same as
+ * the one from original buffer in step 1.
+ */
+
+ hb_buffer_t *fragments[2] {hb_buffer_create_similar (buffer),
+ hb_buffer_create_similar (buffer)};
+ hb_buffer_set_flags (fragments[0], (hb_buffer_flags_t (hb_buffer_get_flags (fragments[0]) & ~HB_BUFFER_FLAG_VERIFY)));
+ hb_buffer_set_flags (fragments[1], (hb_buffer_flags_t (hb_buffer_get_flags (fragments[1]) & ~HB_BUFFER_FLAG_VERIFY)));
+ hb_buffer_t *reconstruction = hb_buffer_create_similar (buffer);
+ hb_buffer_set_flags (reconstruction, (hb_buffer_flags_t (hb_buffer_get_flags (reconstruction) & ~HB_BUFFER_FLAG_VERIFY)));
+ hb_segment_properties_t props;
+ hb_buffer_get_segment_properties (buffer, &props);
+ hb_buffer_set_segment_properties (fragments[0], &props);
+ hb_buffer_set_segment_properties (fragments[1], &props);
+ hb_buffer_set_segment_properties (reconstruction, &props);
+
+ unsigned num_glyphs;
+ hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
+
+ unsigned num_chars;
+ hb_glyph_info_t *text = hb_buffer_get_glyph_infos (text_buffer, &num_chars);
+
+ bool forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
+
+ if (!forward)
+ hb_buffer_reverse (buffer);
+
+ /*
+ * Split text into segments and collect into to fragment streams.
+ */
+ {
+ unsigned fragment_idx = 0;
+ unsigned start = 0;
+ unsigned text_start = 0;
+ unsigned text_end = 0;
+ for (unsigned end = 1; end < num_glyphs + 1; end++)
+ {
+ if (end < num_glyphs &&
+ (info[end].cluster == info[end-1].cluster ||
+ info[end].mask & HB_GLYPH_FLAG_UNSAFE_TO_CONCAT))
+ continue;
+
+ /* Accumulate segment corresponding to glyphs start..end. */
+ if (end == num_glyphs)
+ text_end = num_chars;
+ else
+ {
+ unsigned cluster = info[end].cluster;
+ while (text_end < num_chars && text[text_end].cluster < cluster)
+ text_end++;
+ }
+ assert (text_start < text_end);
+
+ if (0)
+ printf("start %u end %u text start %u end %u\n", start, end, text_start, text_end);
+
+#if 0
+ hb_buffer_flags_t flags = hb_buffer_get_flags (fragment);
+ if (0 < text_start)
+ flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_BOT);
+ if (text_end < num_chars)
+ flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_EOT);
+ hb_buffer_set_flags (fragment, flags);
+#endif
+
+ hb_buffer_append (fragments[fragment_idx], text_buffer, text_start, text_end);
+
+ start = end;
+ text_start = text_end;
+ fragment_idx = 1 - fragment_idx;
+ }
+ }
+
+ bool ret = true;
+ hb_buffer_diff_flags_t diff;
+ /*
+ * Shape the two fragment streams.
+ */
+ if (!hb_shape_full (font, fragments[0], features, num_features, shapers) ||
+ !fragments[0]->successful || fragments[0]->shaping_failed)
+ goto out;
+
+ if (!hb_shape_full (font, fragments[1], features, num_features, shapers) ||
+ !fragments[1]->successful || fragments[1]->shaping_failed)
+ goto out;
+
+ if (!forward)
+ {
+ hb_buffer_reverse (fragments[0]);
+ hb_buffer_reverse (fragments[1]);
+ }
+
+ /*
+ * Reconstruct results.
+ */
+ {
+ unsigned fragment_idx = 0;
+ unsigned fragment_start[2] {0, 0};
+ unsigned fragment_num_glyphs[2];
+ hb_glyph_info_t *fragment_info[2];
+ for (unsigned i = 0; i < 2; i++)
+ fragment_info[i] = hb_buffer_get_glyph_infos (fragments[i], &fragment_num_glyphs[i]);
+ while (fragment_start[0] < fragment_num_glyphs[0] ||
+ fragment_start[1] < fragment_num_glyphs[1])
+ {
+ unsigned fragment_end = fragment_start[fragment_idx] + 1;
+ while (fragment_end < fragment_num_glyphs[fragment_idx] &&
+ (fragment_info[fragment_idx][fragment_end].cluster == fragment_info[fragment_idx][fragment_end - 1].cluster ||
+ fragment_info[fragment_idx][fragment_end].mask & HB_GLYPH_FLAG_UNSAFE_TO_CONCAT))
+ fragment_end++;
+
+ hb_buffer_append (reconstruction, fragments[fragment_idx], fragment_start[fragment_idx], fragment_end);
+
+ fragment_start[fragment_idx] = fragment_end;
+ fragment_idx = 1 - fragment_idx;
+ }
+ }
+
+ if (!forward)
+ {
+ hb_buffer_reverse (buffer);
+ hb_buffer_reverse (reconstruction);
+ }
+
+ if (likely (reconstruction->successful))
+ {
+ /*
+ * Diff results.
+ */
+ diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0);
+ if (diff & ~HB_BUFFER_DIFF_FLAG_GLYPH_FLAGS_MISMATCH)
+ {
+ buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "unsafe-to-concat test failed.");
+ ret = false;
+
+ /* Return the reconstructed result instead so it can be inspected. */
+ hb_buffer_set_length (buffer, 0);
+ hb_buffer_append (buffer, reconstruction, 0, -1);
+ }
+ }
+
+out:
+ hb_buffer_destroy (reconstruction);
+ hb_buffer_destroy (fragments[0]);
+ hb_buffer_destroy (fragments[1]);
+
+ return ret;
+}
+
+bool
+hb_buffer_t::verify (hb_buffer_t *text_buffer,
+ hb_font_t *font,
+ const hb_feature_t *features,
+ unsigned int num_features,
+ const char * const *shapers)
+{
+ bool ret = true;
+ if (!buffer_verify_monotone (this, font))
+ ret = false;
+ if (!buffer_verify_unsafe_to_break (this, text_buffer, font, features, num_features, shapers))
+ ret = false;
+ if ((flags & HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT) != 0 &&
+ !buffer_verify_unsafe_to_concat (this, text_buffer, font, features, num_features, shapers))
+ ret = false;
+ if (!ret)
+ {
+#ifndef HB_NO_BUFFER_SERIALIZE
+ unsigned len = text_buffer->len;
+ hb_vector_t<char> bytes;
+ if (likely (bytes.resize (len * 10 + 16)))
+ {
+ hb_buffer_serialize_unicode (text_buffer,
+ 0, len,
+ bytes.arrayZ, bytes.length,
+ &len,
+ HB_BUFFER_SERIALIZE_FORMAT_TEXT,
+ HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS);
+ buffer_verify_error (this, font, BUFFER_VERIFY_ERROR "text was: %s.", bytes.arrayZ);
+ }
+#endif
+ }
+ return ret;
+}
+
+
+#endif